Piston



(No Model.) 4

W. BAXTER.

lPISI'ON. No. 269,558. Patented Dec. 26, 1882.

4 All UNTTED STATES PATENT OFFICE.

WILLIAM BAXTER, OF JERSEY CITY, NEW JERSEY.

PlSTON.

SPECIFICATION forming part of Letters Patent No. 269,558, dated December 26, 1882.

Application tiled February 10, 1882. (No model.)

To all whom it may concern.-

Be it known that I, WILLIAM BAXTER., acitizen of the United States, residing in the city of Jersey City, in the county of Hudson and State ot' New Jersey, have invented certain new and usef'ul Improvementsin Pistons, fully described and represented in the followl ing specification and the accompanying draw# ings, forming a part of the same.

My invention relates to an improvement in steam-pistons; and it consists inaspecial construction tor the external packing-rings and the means employed for setting them out.

The object of my invention is primarily to produce a piston capable of moving securely over the edges of the ports enteringa cylindrical steam-chest, and its construction is such tha-t the outer packing-rings can beheld rigidly after setting out, to adapt them to move over such ports substantially as if'solid.

A piston constructed as herein described is of course applicable to any cylinder, and may be used in a water-motor or the working-cylinder of any engine.

In the drawings annexed, Figure lisa view o't' the piston A with the follower B removed. Fig. 2 is, a section on line x x in Fig. l. Fig. 3 is au edge view of the external rings detached; Fig. 4, an edge view of the expanding ring, and Fig. 5 an outside view of the followerB; Fig, 6, a side and Fig. 7 a plan view of Inodilied means for adjusting the packing.

A is the body of the piston; B, the follower, secured to the body by bolts C, as usual.

D is a hub, provided with a central hole, E, for the insertion of the rod.

F is an inner ring, cast upon the body, to support a continuous or solid conical ring, G.

H is a split expanding ring, made parallel upon the outside to t the packing-rings I and turned with a taper upon its interior to it the ring Gr. The ring I is shown formed of three annular sections litted together at their adjacent edges by a tongue and groove, b, Fig. 2, to prevent any slipping of one upon another transversely to their axis, each section being cut at a to permit expansion and the ringsadjusted (and pinned together, if desired,) to keep the cuts at different parts of the circumference, as usual. The rings F and H are preferably scraped a little looser when being litted than the packing'rings l, so that the latter may be clamped bythe screwing of follower up to the head. The ringG is iliade sufficiently narrower than the ring H to permit it to move inside the latter-and expand it by the action of the opposed conical surfaces. To produce such movement, screwsfaretted tolugsd, attached tothe interior of the ring G, and the heads of the screws are-extended through the follower, so as to be turned at pleasure from the outside. The heads ofthe screws are formed with a square, h, for that purpose, and a collar, g, provided upon the neck of the screw prevents it from moving endwise by contact with the inside ofv the follower. 'lo accommodate the lugs d, the ring F is formed with recesses c, and recesses J are also shown in the outside ofthe follower for the heads of the screws C andf.

From the above description it will be seen that the contact of metal is continuous from the solid ring F outward to the .surface of the pa'ckingrings, so that the piston is as firm when screwed up as if solid.

The great expense ot' grindingin solid piston-valves may be largely saved by litting such pistons as the above in their place and expanding the'same from time to time as the rings or cylinder wear. When thus applied the wearvcan be fully compensated and great loss of steam saved, which is incurred by the use of solid valves after they have worn too v small for their seats.

It is obvious that two annular sections could be psed for the ring I; but with some sacrifice to the support secured to their several sections. Such an arrangement is shown at Fig. 6, where the several screws fare shown geared together to move in unison. The necks of the screws are extended beyond the surface of the follower and provided with cog-wheels A cogwheel,j, mounted upon a bolt, k, in the center of the follower, serves to gear all the wheels 17 together, and a head, h, is therefore provided upon only one ofthe screws,by which they may all be turned equally' and at the same time.

This attachment insures a uniform expansion 'ot' the packing-ring without any special attention from the operator. The cog-wheels are merely indicated in Fig. 7 by dotted circles. Asiinpler device for securinga uniform IOO rotation ofthe screws is shown in Fig. 5, where the head of one ofthe screws is marked with au arrow, a, and the margin of the recess J is provided with graduations l, by which the relative position of the several screws can be readily observed and their position accurately adjusted.

By applying the graduations l and arrow a to all the screws the operator would possess the means of turning them all uniformly.

I am aware that conical rings have been used before to set out packing-rings in a piston both in combination with springs and with setscrews tapped through the follower B, and I do not therefore claim such a device, broadly; but my construction presents several points ot' difference from any previously known, and as these points secure, very material advantages in the vuse and satisfactory working ofthe piston, I consider them as valuable improvements upon former inventions. llhus the conical ring Gis so constructed by me that it can he turned of a circular shape internally, and thus iitted snugly to a supporting-ring, F, which has not been heretofore used Jt'or such a purpose. The use of the ring F, formed rigidly upon the body-plate A and extending into oo ntact with the follower7 not only keeps the conical ring` G concentric, but braces it to force outward strongly, and it thus makes the entire set of rings as solid and immovable as if integral with the head or body A. The provision ofthe tougue-and-groove joint b in the outer rings, I, also secures the saine object and prevents any possible displacement ot' the separate rings in passing over ports or such annular passages as are common in piston-valve chests. lThe provision of collars g upon the adjusting-screws f and the formation of the nut in the lugs d instead of in the follower B, as has been done heretofore, prevent any projection of the screws outside the piston, and thus enables the same to work closer to the heads ofthe steam chest or cylinder, and the whole, construction thus affords a combination not only more perfect in itsoperaiion, but more suitable for certain purposes, than those heretofore made.

Having thus fully described my invention, it will be seen tha-tmy construction is adapted to produce a very tirm packing for a piston, and that the latter can be adjusted with great ease and accuracy to tit the cylinder. I theretore claim the saine in the following manner:

In a piston, the conibinatiomwi'th the follower B and the. head A, having asupiiortingring, F, turned to iit the interiorof a movable ring, and provided with recesses e, for the pur'- posc set forth, ofthe conical movable ring G, provided vwith lugs d, and operated by the screwsf, as described, the tapered and cut expanding ring ll and the packing-ring I, formed of annular sections fitted together with tongues and grooves I), substantially as shown and described.

Iu testimony whereof l have hereunto set my hand in the presence of two subscribing witnesses.

WM. BAXTER.

Vitnesses:

I1-ros. S. URANE, II. P. OsBoRNE. 

